HEDGECOCK ET AL.: GENETIC VARIATION IN PACIFIC SARDINES 



Table 4. — Classification functions and a posteriori (jackknifed) 

 classifications from discriminant function analyses of similarly 

 sized Pacific sardines from (A) California and (B) Mexican popu- 

 lation samples. 



2871.099 



-537.635 



591.291 



-1949.291 



zygosities range from 6.99c in the inshore Half 

 Moon Bay and Point Dume samples to 8.0% in 

 the middle Santa Monica Bay sample, with a 

 mean over the nine samples of 7.59c (95% C.L.: 

 7.1-7.9%). There are no significant differences 

 between observed and expected average hetero- 

 zygosities in any of the samples. 



Sample sizes and levels of polymorphism per- 

 mit goodness-of-fit tests to H-W-C genotypic 

 proportions in 27 cases, involving five loci — 

 Fum, Hbdh-2, Lgg, Pgm, and Xdh. Prior to 14 of 

 these tests, rare alleles were pooled and the fre- 

 quencies of composite genotypic classes recalcu- 

 lated accordingly (Pamilo and Varvio-Aho, 

 1984). The probabihty assigned to a significant 

 deviation from the H-W-C (null) hypothesis, 

 ■Pao.05, was adjusted for multiple testing by 

 dividing ao,,,, by the number of populations over 

 which a given locus was simultaneously tested 

 (Cooper 1968). None of the 27 tests is significant 

 at the adjusted ao.0.5 level, although chi-square 

 values for Hhdh-2 in the offshore Santa Cruz 

 sample and for Lgg in the Point Dume sample 

 come close. 



Deviations from H-W-C equilibrium for 

 Hbdh-2 and Lgg tend towards excess hetero- 



zygotes. Wright's (1978) fixation indices (f is) for 

 Hbdh-2 in population 4 and for Lgg in populations 

 4, 6, and 8 (four chi-square tests with P =s 0.06) 

 are -0.49, -0.37, -0.36, and -0.19, respec- 

 tively. Averaged over populations and alleles, 

 Fis for Hbdh-2 and Lgg is -0.13 and -0.175, 

 respectively; the weighted average f ig over all 

 loci is -0.045 (see Table 7). There is, owing to 

 these excesses of heterozygotes within popula- 

 tion samples, an overall excess of heterozygotes 

 in the total population sampled (mean i^ij over 

 all loci and populations is -0.012), despite diver- 

 gence among populations (next section), which is 

 expected to reduce heterozygosity (Wahlund 

 1928). 



Genetic Variation Between Populations 



Eleven loci were polymorphic enough 

 throughout the nine population samples (Table 6) 

 to permit analyses of geogi'aphical heterogeneity 

 in allelic frequencies. Rare alleles were pooled 

 into one class for all but the Lgg and Xdh loci, for 

 which two rare-allele classes were formed. The 

 resulting two- or three-by-nine matrices were 

 tested for r x c independence by log-hkelihood 



661 



